This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
18. Newel posts, or newels, are used to support the hand rail, and are either made of solid materials and turned, or built up, box-like, in which case they are called boxed novels. They vary in design, form, and size, some-especially those placed at the bottom of the stairway, called the starting newel - often being elaborately decorated with panels and carvings.
The newel is also variously fixed in its relation to the steps adjoining. In ordinary cases it is placed on the floor, and when so placed its center should be in line with the center of the first riser. Where space is limited at the bottom of a stairway, the newel maybe placed on top of the first step, and even on top of the second or third step; but in each case, it is desirable to place it so as to have the center of the riser at the newel center, and the steps outside rounded, and returned into the stringer; the end of the latter being inserted in a prepared mortise in the center of the newel.
The angle newels on the landings are generally smaller in size and have less decoration than the starting newels. The same rule applies to their relation to the risers; viz., that the center of the riser connecting should be at the center of the newel. Working from centers in stair-building construction is almost a maxim. The center of the rail is to be in the center of the newel; so, also, is the center of the stringer; and the center of the baluster is to be in the center of both stringer and rail; and, as above mentioned, the center of the riser adjoining the newel is to be placed at the center of the latter.
19. Balusters are small columns, generally turned, set vertically on the ends of treads, forming an ornamental guard, and at the same time supporting the hand rail. When the front stringer is a closed, or housed, one, the balusters are fixed to the stringer, instead of to the treads, a grooved molding, called a cap, being prepared to receive them; the lower end of the balusters in this case are cut to the pitch of the stairway, and the top is either cut to the same pitch as the rail, or mortised into it. This applies to balusters having square ends. Frequently they are made square or round at the bottom, and turned to a spindle shape at the top, being then termed pin balusters. Balusters with square bases are preferable to those with round bases, as the square base gives bearing surface and resistance to movement almost double that of a round base. Holes are bored about an inch deep into the under side of the rail to receive the balusters, and the lower ends are either cut to the pitch of the stairway or dovetailed to the ends of the treads, depending on whether the stringer is housed or cut and mitered.
In ordinary stairways, two balusters are used to each tread, but in the better class of stairways, the number is increased, adding thereby to the beauty and strength of the balustrade, and general appearance of the stairway. With two balusters on a tread, they are placed half the width of a tread apart between centers, the short one standing close to the nosing and the long baluster being placed midway between the adjacent nosing balusters, so that it is exactly one-half the rise of the steps longer than the short one on the same tread. The usual height of pin balusters is either 2 feet 4 inches or 2 feet 8 inches, of which 1 inch is allowed at each end for insertion into rail and tread.
In extra fine stairways the space between the balusters is filled in with brackets of various designs, or the space is paneled; in either case the number of balusters is reduced to one for each tread, ordinarily placed over the face of each riser, thus leaving the full width of the tread (less the thickness of one baluster) for the decorative brackets or panels.